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Simple Dependency Resolver in PHP. Dependency Autowiring.
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| <?php | |
| /* | |
| * USAGE: | |
| * | |
| * // this is where I define all my dependencies in case if they are not directly instantiable (resolvable) | |
| * $deps = array( | |
| * 'DependentClass' => array( | |
| * 'depclass' => 'DependencyClass' | |
| * ) | |
| * ); | |
| * ObjectManager::getInstance()->setDependencies($deps); | |
| * | |
| * class DependentClass { | |
| * private $depclass; | |
| * private $dep2; | |
| * function __constructor(DependencyClassInterface $depclass, DirectlyResolvableClass $dep2) { | |
| * $this->dep2 = $dep2; | |
| * $this->depclass = $depclass; | |
| * } | |
| * function doSomething() {} | |
| * } | |
| * | |
| * ObjectManager::getInstance() | |
| * ->get('DependentClass') | |
| * ->doSomething(); | |
| * | |
| */ | |
| class ObjectManager | |
| { | |
| protected $dependencies; | |
| protected static $omInstance; | |
| public static function getInstance() | |
| { | |
| if (!self::$omInstance) { | |
| self::$omInstance = new ObjectManager(); | |
| } | |
| return self::$omInstance; | |
| } | |
| public function setDependencies(array $dependencies) | |
| { | |
| $this->dependencies = $dependencies; | |
| } | |
| public function getDependencies() | |
| { | |
| return $this->dependencies; | |
| } | |
| public function get($class) | |
| { | |
| $finalizedParams = array(); | |
| $deps = array(); | |
| // check if deps are defined | |
| if (array_key_exists($class, $this->dependencies)) { | |
| $deps = $this->dependencies[$class]; | |
| } | |
| $reflector = new ReflectionClass($class); | |
| if (!$reflector->isInstantiable()) { | |
| throw new Exception("Class {$class} is not instantiable"); | |
| } | |
| $constructor = $reflector->getConstructor(); | |
| if ($constructor == null) { | |
| return $reflector->newInstance(); | |
| } | |
| $parameters = $constructor->getParameters(); | |
| foreach ($parameters as $key => $parameter) { | |
| $parameterType = $this->getParameterType($parameter); | |
| $parameterName = $parameter->getName(); | |
| if ($parameterType == null) { | |
| if ($parameter->isDefaultValueAvailable()) { | |
| $finalizedParams[$key] = $parameter->getDefaultValue(); | |
| } else { | |
| throw new Exception(" | |
| Failed resolving argument (dependency) \"$parameterName\" for class $class. | |
| Not directly instantiatable. | |
| No default value specified."); | |
| } | |
| continue; | |
| } | |
| $classReflection = new ReflectionClass($parameterType); | |
| // if dep is directly instantiable; save and continue | |
| if ($classReflection->isInstantiable()) { | |
| $finalizedParams[$key] = $classReflection->newInstance(); | |
| continue; | |
| } | |
| // if defined in di.php | |
| if (array_key_exists($parameterName, $deps)) { | |
| $argName = $deps[$parameterName]; | |
| $finalizedParams[$key] = ObjectManager::getInstance()->get($argName); | |
| continue; | |
| } | |
| } | |
| return $reflector->newInstanceArgs($finalizedParams); | |
| } | |
| protected function getParameterType(ReflectionParameter $parameter) | |
| { | |
| $export = ReflectionParameter::export( | |
| array( | |
| $parameter->getDeclaringClass()->name, | |
| $parameter->getDeclaringFunction()->name, | |
| ), | |
| $parameter->name, | |
| true | |
| ); | |
| return preg_match('/[>] ([A-z]+) /', $export, $matches) | |
| ? $matches[1] : null; | |
| } | |
| } |
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